The first entry is always the pin's source. Overall confidence is a weighted average of how firmly each reference supports the start and end times used above; a reference counts half as much for every 180 days older than the newest.
Wikipedia[3][5][6] lists iOS on 11 July 2013; IGN's[2] 7 June 2013 article (opened) contains the date; Steam lists the Windows version at 17 Mar 2014 (Wikipedia 18 March).
IGN article page containing the 11 July 2013 date.
Series article listing the entry in the franchise's release order.[1]
Steam store page for the PC release; lists a Steam release date of Mar 17, 2014.[1]
Developer or studio page.[1]
Something missing or wrong? Say it in your own words: a link that backs this pin up, a different start or end date and why, or a fact it lacks or gets wrong. The AI checks it against this pin's sources, searches for better ones, and adds any page that backs you up. The pin's own sources still count most. A picture that shows something else, or shows it badly, is looked at too, and moved down or replaced.